A color developer containing an aromatic primary amine color developing agent has hitherto been utilized for the formation of photographic color images, and at present, and continues to have a main role in image formation methods in color photography. However, the color developer has a problem in that it is extremely easily oxidized in the presence of air or metals, and it is well known that the use of the oxidized developer for the formation of color images can cause an increase of fog and fluctuation of the sensitivity or gradation, with the result that the desired photographic characteristics can not be obtained.
Under the situation, various means have heretofore been investigated so as to improve the preservability of color developers, and among them, a method of using both hydroxylamine and a sulfite ion is most general. However, the hydroxylamine yields ammonia, which, when decomposed, causes the generation of fog, while the sulfite ion also is a problem, in that it acts as a competing compound for the developing agent, to interfere with the coloring property thereof. Accordingly, it is difficult to say that both of these compounds are preferred as the compound (preservative) for improving the preservability of the color developer. In particular, when the sulfite ion is used in a system not containing benzyl alcohol, which is harmful during preparation of the developing solution (developer) in view of environmental pollution problems, this causes an extreme lowering of the color density of the image formed.
As a compound capable of being used in place of sulfites, the alkanolamines described in Japanese Patent Application (OPI) No. 3532/79 (the term "OPI" as used herein means a "published unexamined Japanese patent application") and the polyethylene imines described in Japanese Patent Application (OPI) No. 94349/81 have been proposed, but even these compounds could not attain a fully satisfactory result.
In particular, a color photographic material having a silver chlorobromide emulsion with a high chlorine content is often fogged during color development (Japanese Patent Application (OPI) Nos. 95345/83 and 232342/84. Accordingly, when such emulsion is used, a preservative is indispensable which has a low solubility in the emulsion and which has a higher preserving function. However, a fully effective preservative has not yet been found.